98It is true that all the activities of airport operators are not necessarily economic in nature. Activities which fall within the exercise of public powers are not of an economic nature justifying the application of the EC Treaty rules of competition (MOTOE, paragraph 88 above, paragraph 24 and the case-law cited). The classification as an activity falling within the exercise of public powers or as an economic activity must be carried out separately for each activity engaged in by a given entity (MOTOE, paragraph 88 above, paragraph 25).